Patent Document 1 discloses a drive assist device that guides a parking operation when attempting to parallel park in a parking space aligned with an access road or when attempting to park perpendicularly. With this drive assist device, the vehicle periphery is captured by cameras installed in multiple positions on the vehicle, an overhead image is created by converting and synthesizing the captured image signals into an image signal whose point of view takes the camera optical axis as perpendicular to the road surface, a guidance indicator is set based on the current position of the vehicle in the overhead image, a superimposed image in which the guidance indicator is overlaid on the overhead image is created, and the superimposed image is displayed in a display means. At this time, a front outermost edge guidance indicator, a rear outermost edge guidance indicator, and a rear innermost edge guidance indicator are presented as guidance indicators for backing into a perpendicular parking space. The front outermost edge guidance indicator is a fan shape whose outer edge is an arc corresponding to ¼ of a turning circle trajectory, whose center is the turning center point of the vehicle and that passes through the left-front end of the vehicle body. The rear outermost edge guidance indicator is a fan shape whose outer edge is an arc corresponding to ¼ of a turning circle trajectory, whose center is the same turning center point and that passes through the rear end portion of the vehicle. The rear innermost edge guidance indicator is an arc corresponding to ¼ the turning circle trajectory whose center is the same turning center point and that passes through both end portion of the vehicle. In this manner, setting the trajectories of the end portion of the vehicle body as guidance indicators based on the current position of the vehicle in the overhead image and displaying those indicators superimposed over the overhead image in a monitor is intended to enable the driver to easily understand a position of entry into the parking space. However, in this drive assist device, the trajectories of the vehicle end portion that serve as the guidance indicators are based on the minimum rotation (turning) radius of the vehicle, and thus the device is not suited for assisting driving when switching the steering angle from one direction to the steering angle in the opposite direction. Furthermore, guidance indicators based on the minimum rotation radius are difficult to use during driving in which the steering angle is changed frequently, such as a head-in parking process in which the vehicle advances into the parking space while traveling forward, a parking space departure process in which the vehicle advances out of a parking space on either side of which vehicles are parked, and so on where a relaxed steering angle with a large turning radius is used in the first half of the process.